What should I keep in mind during a hard reset?

So here's the deal. I updated my phone last night to 8.1+Cyan. And my other storage has a huge chunk of data. About 1.8GB. And only 2.7 free memory left. I was thinking of doing a hard reset and sorting out the problems.. I want to know what I should keep in mind before a hard reset. Is there any other alternatives to sorting this out? My phones a bit slower than before. Perhaps 'cause of the huge app cache. The second reason I want to do this is because I want to switch from my old live account to my new hotmail account. Can somebody help?

Go into settings->backup and ensure that you have all three items set to "backup on"

Tap on the "apps+settings" item and hit the "backup now" button.

In your photo hub, ensure that all of the photos on your phone have been synchronised to OneDrive (or your preferred photo storage site).

That's basically it. You'll get your apps downloaded afterwards and most of the settings (depends how good the apps are). However, if you have apps that you know are bloated, uninstall them first to be on the safe side before you run the apps+settings backup(will minimise risk that you may get your bloat back on the restore).

The whole hard reset thing is a heck of a lot less painful now than it used to be.

If you use a different Microsoft Account during the setup after you perform the hard reset, you will get nothing back at all - all apps/settings are tied to that account.

If you're using the same Microsoft Account, then yes all of the apps that were installed before the hard reset will come back and be automatically restored. Text messages will also come back, but it can take a while depending on how many messages there are.